Centrifugal bowl



March 7, 1950 G. J. STREZYNSKI CENTRIFUGAL BOWL Filed Aug. 10, 1946 ggs 1 II II M .INVENTOR GEORGE J. STREZYNSKI Patented Mar. 7, 1950 UNITED STATES PATENT OF F ICE' 8 Claims. 1

This invention relates to centrifuges for sepferent specific gravities, each from the other,

and has for its object to provide an improved centrifuge for this purpose which is especially adapted for the separation of two solids of different specific gravity, each from the other and from a common carrier liquid.

The new centrifuge may be used for eifecting a separation of various mixtures. For illustrative purposes, however, it will be described in connection with the production of starch, in a form suitable for separating the starch, gluten and water constituents of the tailings from standard starch tables. A process for eil'ecting such separation is disclosed in my co-pending application Serial No. 689,669, filed August 10, 1946. Patent No. 2,488,747, granted November 22, 1949; and the present invention may be used to advantagein the practice of that process.

One feature of the present invention resides in a centrifuge for effecting a three-way separation region of the bowl where the heaviest constituent accumulates, into the secondary separating chamber, whereby a scrubbing action is obtained.

Still another feature is a centrifuge of the character described having a series of conical blank discs in the primary separating chamber and between which the heaviest constituent is separated from the two lighter constituents, the latter then moving to one surface of the blind disc from near the inner edges of the blank discs, and outwardly along the blind disc and around its outer edge into the secondary chamber which, in turn, contains a second series of conical discs but perforated to allow separate discharge of the two lighter constituents separated between these discs.

An additional feature is a centrifuge, especially adapted for separating the tailings from starch tables, in which the separated water constituent is used to dilute and flush the separated starch through peripheral outlets in the bowl, by returning at least part of the discharged water to A top disc It provides a division wall between through a flushing tube to the peripheral portion of the bowl outside the separating region, whereby the flushing water is not admixed with the separated gluten.

These and other features of the invention may be better understood by reference to the accompanying drawing, in which the single figure is a vertical sectional view of part of a centrifuge made in accordance with the invention.

The centrifuge comprises a bowl shell I having a bottom 2 with a central socket 3 for receiving the driving and supporting spindle 4. An annular biowletop 5 is secured to the shell I by coupling r ng The tailings from the starch tables, consisting of a mixture of water, starch and proteins (commonly called glutenh and possibly other impurities, is fed into the bowl through a stationary tube I. The tube 1 extends into a tubular distributing shaft 8 which is arranged on the bowl axis and rotates with the bowl. At its lower end portion, the tubular shaft forms with the socket 3 an annular distributing chamber 9 having a series of radial holes 9' leading outward to a primary separating chamber 40. As shown, the holes 9' are spaced throughout substantially the entire height of the separating chamber Ill.

Within the primary chamber I0 is a series of conical discs ll partly defining at theirinner edges a plurality of generally vertical passages ID, the outer edges of the discs being spaced a substantial distance from the peripheral portion of the bowl. The discs I l are blank, that is, they are imperforate except for central openings for the tubular shaft 8 and the passages I0. At their upper ends, the passages I0 are terminated by a blind conical disc l2, likewise imperforate, sealed at its inner edge to the tubular shaft 8, as shown at l2. The blind disc I! also has a substantial clearance between its outer edge and, the peripheral portion of the bowl.

Above the discs i l and separated therefrom by the blind disc I2 is a secondary separating chamber having a series of conical discs l3 similar in size and shape to the discs H. The discs it, however, have two groups of distributing holes, one group It being located near the outer edges of the discs, and the other group 15 being located nearer the bowl axis. It will be apparent that the upper or secondary separatingchamber has communication with the lower chamber It only around the extreme outer edge of the blind disc I2, because of the liquid-tight Joint provided 'by the seal l 2'.

the upper separating chamber and a discharge passage II, the upper chamber having communication with the passage ll only through holes l8 arranged directly over the disc distributing holes II. The top disc I. is so constructed that it makes at its outer extremity a liquid-tight joint with the bowl top 8, as shown at It. At its inner end, the passage l1 leads upward between the bowl top-Q and a neck on the top disc II, to an outlet ll.

The inner edges of the upper discs II and the tubular shaft I define generally vertical passages I la leading'upward, within the neck of top disc I, to a second discharge outlet II which may be restricted by a discharge ring ll.

Nozzles 23 in the wall of the bowl shell provide a third discharge outlet from the peripheral portion of the bowl, a substantial distance outward from the edge of blind disc II.

In the operation of the bowl, the tailings fed to the interior of tubular shaft I fiow outward through the distributing holes I to the inner portion of the primary separating chamber Ill and into the spaces between the blank discs H, where a separation of the major portion'of the relatively heavy starch solids 'takes place. Since starch will separate readily from the gluten and water, it is-practicable to direct the feed by holes 9' to a zone of relatively small centrifugal force. The starch; separated between the blank discs H is forced directly outward, with some water, into the peripheral portion I of the separating chamber of the bowl and is continuously discharged through the nozzles 23. The remainder of the feed, comprising primarily gluten and water of lower specific gravity than the starch, flows inward toward the bowl axis and then upward along the passages l0, until it reaches the blind disc i2. The flow of the lighter constituents is then directed along the lower surface of disc I2 to its extreme outer edge. This passage of the lighter constituent through a zone of greater centrifugal force than that to which it was originally subjected will remove the last traces of starch which may have been present in the water and gluten mixture. Moreover, some of the water which is forced directly outward from the discs with the separated starch will tend to flow upward along the outer edges of the discs and rejoin the lighter separated constituents flowing around the disc l2, whereby a washing or scrubbing action of the starch particles is obtained.

I After passing around the outer edge of blind disc II, the mixture of gluten and water flows inwardly between the upper discs I; to the distributing holes I4. Between the discs l3, a separation of the gluten from'the water takes place, the heavier gluten passing through holes ll and outlet holes ll in the top disc and then along the discharge passage I! to the outlet IS. The water flows inward toward the bowl axis and then upward along passage "a through the discharge ring 2|, finally escaping at the outlet 20. However, in the event that any portion of the gluten,

the neck ofthe top disc I! isless than the radius B of the center holes in discs ll, which holes provide the generally vertical passages Ila.

The discharges through outlets 23, I9 and Il may be collected in suitable covers having spouts 25, 25 and 21 respectively.

I have found that in separating starch in a relatively pure condition from the tailings, there is a'strong tendency for the starch to clog its discharge outlets 23. Accordlngly, I prefer to utilize the relatively pure separated water from the out.- let 20 for diluting the separated starch and fiushing it from the bowl. To this end, at least part of the water from the spout 21 is led through pipes 28 and 29 to a nozzle 30 which ieeds the water into an inwardly facing annular recess 31 in the bottom of the bowl. From the recess II. the water is forced outwardly by centrifugal force through flushing tubes 32, mounted in the bottom 2 and extending into the bowl, the tubes 32 terminating at their outer ends near the entrances to the nozzles 23. It will thus be apparent that the separated flushing water is fed to the bowl at a region where it is eifective to flush the separated starch solids through outlets a, but in a region outside the separating zone in the bowl. Accordingly, the separated fiushing water is not admixed or further contaminated with the separated gluten flowing around the outer edge of the blind disc l2, whereby the flushing water may be more readily recovered or reconditioned for further use.

It will be apparent that the holes 9' in the distributing chamber 8 provide an inlet to the primary chamber III for feeding thereto the mixture to be separated, and that the opening I! in the top disc provide an outlet from the secondary chamber for discharging the separated constituent of intermediate specific gravity. The peripheral outlet from the primary chamber III is the annulus lying between the outer edge of blind disc I! and the bottom of the bowl, and the throughfiow area of this peripheral outlet is at least equal to the throughfiow area of the primary chamber inlet provided by the holes 9'.

Certain features of the centrifuge disclosed herein are the subject matter of a co-pending application of G. F. Wheelwright, Jr., Serial No. 689,738, filed August 10, 1946, patented August 16, 1949, No. 2,478,922, and I make no claim to such features.

I claim:

1. A centrifuge for separating a mixture of three constituents of different specific gravlties, each from the others, which comprises a centrifugal bowl having primary and secondary separating chambers, an inlet to the primary chamber for feeding thereto the mixture to be separated, an outlet from the secondary chamber for discharging the lightest separated constituent and located near the bowl axis, an outlet from the secondary chamber for discharging the separated constituent of intermediate specific gravity and located radially between the bowl periphery and the first outlet, and a blind disc for separating said chambers and extending outward beyond said outlets but having a substantial clearance space betweenits outer edge and the bowl periphery, the primary chamber having a peripheral outlet partly defined by the outer edge of the blind disc and of at least the throughfiow area of said inlet to the primary chamber, whereby the heaviest separated constituent is forced outward di-' rectly through the peripheral outlet from the primary chamber and toward the bowl periphery,

and the two lighter constituents are forced against said blind disc and flow outward alon the surface, through the adjacent part of said last outlet, and through said clearance space-to the secondary chamber for separation and discharge of the lighter constituents through their respective outlets.

2. A centrifuge as defined in claim 1, comprising also a series of conical discs in the primary chamber partly defining near the bowl axis a generally vertical passage for the lighter constituents separated between the discs, the passage terminating at the blind disc.

3. A centrifuge as defined in claim 1, comprismediate specific gravity and located radially between the bowl periphery and the first outlet,

and a blind disc for separating said chambers and extending outwardly between the chambers but having a substantial clearance between its outer edge and the bowl periphery, and a series ing also a series of conical'discs in the primary of spaced conical discs in each of said chambers,

chamber with their inner edges disposed radially outward from said inlet, the discs partly defining near the inlet a generally vertical passage for the lighter constituents separated between the discs, the passage terminating at the blind disc.

4. A centrifuge as defined in claim 1, comprising also a series of conical discs in the secondary chamber partly defining a generally vertical passage for the heavier constituent separated between the discs, said last passage being within the outer limit of the secondary chamber and at the same radius as said second outlet.

5. A centrifuge as defined in claim 1, comprising also a series of conical discs in the secondary chamber partly defining three generally vertical passages at different radii from the bowl axis and located within the outer limit of the secondary chamber, the innermost passage be-.

ing for the lighter constituent separated between said discs and leading to said first outlet, the outermost passage being for the heavier constituent separated between the discs and alined vertically with said second outlet, and the third passage communicating with said outlets only along the disc surfaces.

6. A centrifuge as defined in claim 1, comprising also a series of conical discs in the primary chamber, and a tubular shaft for receiving the mixture to be separated and having, as said inlet, a. series of peripheral distributing holes arranged at difierent levels and leading outward to the primary chamber at the inner edges of said discs.

7. A centrifuge for separating a mixture of three constituents ofdiiferent specific gravities, each from the others, which comprises a centrifugal bowl having primary and secondary separating chambers, said chambers opening outwardly into the peripheral portion of the bowl chamber and the primary chamber being of at whereby the heaviest separated constituent is forced outward directly through the peripheral portion of the primary chamber and toward the bowl periphery, and the two lighter constituents are forced against said blind disc and fiow outward along the surface thereof and through said clearance space to the secondary chamber for separation and discharge of the lighter constituents through their respective outlets.

8. A centrifuge as defined in claim 7, in which the discs in the secondary chamber have two sets of vertically alined holes, one set located inwardly from the outer edge of the blind disc and at the radius of said secondary chamber outlet 0 for the separated constituent of intermediate specific gravity, the other set located inwardly from the first set but outwardly from the secondary chamber outlet for the lightest constituents.

GEORGE J. STREZYNSKI.

REFERENCES CITED The following references are of record in the file of this patent:

an outlet from the secondary chamber for discharging the separated constituent of inter-.

Certificate of Correction Patent No. 2,500,100 March 7, 1950 GEORGE J. STREZYNSKI It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 4', line 50, for the patent number 2,478,922 read 2,478,992; column 6, lines 38 and 34, for constituents reed constituent;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 11th day of July, A. D. 1950.

THOMAS F. MURPHY,

Auictant flommiaaioner of Patenlta. 

